Lack of exercise tops the list of the biggest concerns about kids' health, according to a new survey of American adults. The plight of young couch potatoes outranked teen pregnancy and drug abuse as problems that adults are concerned about, according to the survey.

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Not getting enough exercise was ranked a "big problem" by 39 percent of adults surveyed, followed closely by childhood obesity (38 percent) and smoking and tobacco use (34 percent), according to the findings from the University of Michigan C.S. Mott Children’s Hospital National Poll on Children’s Health.

In last year’s survey, childhood obesity topped the list, while “not enough opportunities for physical activities” didn’t even make the top 10. The jump in the adults' concern about exercise may be due recent public health messages focused at this topic, researchers said.

"Childhood obesity remains a top concern, and adults know it is certainly linked to lack of exercise," Matthew Davis, director of poll, said in a statement. "But exercise offers many more benefits other than weight loss or preventing obesity — such as better attention and learning in school and improved sense of well-being," Davis said.

The annual survey results also revealed that 33 percent of adults rated drug abuse as a big problem for children's health, and 29 percent listed bullying as a major concern.

Rounding out the bottom half of the top 10 concerns were stress (27 percent), alcohol abuse (23 percent), teen pregnancy (23 percent), Internet safety (22 percent) and child abuse and neglect (20 percent). The polling sample is representative of the U.S. adult population.

The poll’s results varied with respondents' races and ethnicities. Childhood obesity was the top concern (44 percent) among Hispanic adults, followed by not enough exercise (38 percent).

Black adults listed smoking and tobacco use as their biggest concern (43 percent). They also were more worried about racial inequality, which ranked seventh on their list, and gun-related injuries, which ranked ninth. Both black and Hispanic adults said sexually transmitted infections were a greater concern for kids in their communities than did white adults.

But Hispanic, black and white adults all said that not enough exercise and obesity were two of their top three health concerns for kids in their communities.